1. Field of the Invention
The present invention relates to holdowns for use, for example, in wood frame buildings to connect studs securely to cills or plates.
2. Description of the Related Art
To reinforce the walls of wood or metal frame buildings against racking strains caused, for example, by earthquakes or hurricanes, metal connectors known as "holdowns" are employed to connect studs in the frames to cills and/or plates.
More particularly, holdowns are known which comprise a pair of side walls extending parallel to one another and at right angles to a back, with a flat seat or base portion extending between the side walls at right angles to the side walls and to the back. The seat is formed with an opening through which a fastener, e.g in the form of an anchor bolt partially embedded in a concrete foundation, extends upwardly through a cill and the seat to an upper end, which is in threaded engagement with a nut tightened against the seat to hold the latter down against the cill. One or more fasteners, e.g. bolts or nails, extend through the back for securing the holdown to a stud.
It is found, in practice, that the seat of the holdown may be subject to distortion by forces acting vertically on the holdown and transmitted to the holdown from the stud through the back of the holdown, and it has therefore previously been proposed to counteract such distortion by the provision of a flat metal Washer between the nut and the seat, the washer being substantially coextensive with the seat and in face-to-face contact therewith.
Examples of such holdowns are disclosed in U.S. Pat. Nos. 4,744,192 issued May 17, 1988 to Alfred D. Cummins, 4,665,672 issued May 19, 1987 to Alfred D. Cummins et al., and 5,092,097 issued Mar. 3, 1992 to Donald E. Young.
In Canadian Patent Application No. 2,214,944 by Robert C. Gregg et al., laid open Apr. 10, 1998, there is disclosed a connector having a back, side walls and a seat member in which the seat member is concave and in which an N-shaped washer is seated on the seat member. The N-shape washer, more particularly, has convexly curved parallel edges which extend between and at right angles to the side wall, with opposed edge surfaces of the washer facing the surfaces of the side walls.
It is a disadvantage of this prior holdown that, because the seat member has a convexly curved undersurface, the seat member cannot be seated flush against an underlying cill. During installation of the holdown, it is not possible to place the holdown on the cill and to release it, before fastening it, because the holdown is not self-supporting on the cill.